1. Field of the Invention
The present invention relates to a projection display apparatus including a plurality of solid state light sources.
2. Description of the Background Art
Projection display apparatuses using solid state light sources such as light emitting diodes (LEDs) and lasers as light sources thereof, unlike projection display apparatuses using lamp light sources such as a halogen lamp, a high pressure mercury lamp, a metal halide lamp and a xenon lamp, have an advantage in that the light sources have a longer life. For this reason, the replacement of the light sources has not been considered to be important in the projection display apparatuses using solid state light sources.
On the other hand, a solid state light source includes precise and complicated optical systems such as, for example, three solid state light source elements for red, green and blue, a collimator lens, a combined optical system, and a light collection optical system (a condenser lens). Precise adjustment is required for the replacement of the solid state light source.
Conventionally, the need for the adjustment operation during the replacement is eliminated by integrating a solid state light source and a collective lens (in some cases, referred to hereinafter as a “collimator lens”) together, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-330282. This, however, is based on the assumption that the solid state light source and the collective lens are used together with a lamp light source, and does not assume an instance in which multiple solid state light sources are used to cause the optical axis of irradiation light on the light source side and the optical axis for incident light set on the projection side to coincide with each other.
Little consideration has been given to the replacement of light sources in the conventional projection display apparatuses using solid state light sources. The conventional projection display apparatuses using solid state light sources have a problem in that the adjustment of the optical axes during the replacement of the plurality of solid state light sources is not substantially achieved.